Hello to all
I am new in the group and I wanted to ask you for a simple information.
The project I am building is aleph J but I have encountered problems with the availability of 2sj74.
Is it possible to use a n-channel configuration?
or can you tell me a possible solution?
Thanks so much
Alessandro
I am new in the group and I wanted to ask you for a simple information.
The project I am building is aleph J but I have encountered problems with the availability of 2sj74.
Is it possible to use a n-channel configuration?
or can you tell me a possible solution?
Thanks so much
Alessandro
I think you can get matched monolithic 2LSJ74 (called LSJ689) for $9ea direct from LS. I wonder if legs can be twisted to match pin outs on Aleph J board?
Linear Systems || ULTRA LOW NOISE P-CHANNEL DUAL JFET
Can’t tell if in stock though.
Linear Systems || ULTRA LOW NOISE P-CHANNEL DUAL JFET
Can’t tell if in stock though.
Last edited:
I think it could work just fine even if not exact parameters. Really designed for LTP input stage.
My point is that LSJ689 is not dual LSJ74, it is more similar to dual 2SJ103. Maybe it would work just fine for certain application, but will deviate from Aleph J intended design, especially response and phase of high frequency. For J2, I think Mr. Pass even double the input jfets. In case you have spare matched quads, you can mod your Aleph J by paralleling jfets below the board easily enough for more open and effortless presentation. Input jfet with lower transconductance than the LSJ74 in Aleph J is perhaps less desirable. However everybody is free to try any viable alternative, it's diy after all.
well, 1.5mS is way too wimpy instead of 22mS , so much altering (decreasing) OLG of amp , that this will not be even approximately same amp
if not 2SJ or LSJ , one can use J271 (matched pair) , with xconductance in same ball park
even if they're pretty higher Idss parts , comparing to Toshibas , they're biased by CCS in tail , so no biggie
if not 2SJ or LSJ , one can use J271 (matched pair) , with xconductance in same ball park
even if they're pretty higher Idss parts , comparing to Toshibas , they're biased by CCS in tail , so no biggie
How can you recommend something 20x noisier as substitute ?
http://www.diyaudio.com/forums/solid-state/131224-j270-jfet.html#post1630681
There is just no substitute to 2SJ74.
Maybe 9x 2SJ106Y in parallel would come close. 😉
Merry Christmas,
Patrick
http://www.diyaudio.com/forums/solid-state/131224-j270-jfet.html#post1630681
There is just no substitute to 2SJ74.
Maybe 9x 2SJ106Y in parallel would come close. 😉
Merry Christmas,
Patrick
certainly up to task in power amp input LTP
I didn't recommend it for preamp duty , in thread titled Aleph J
I didn't recommend it for preamp duty , in thread titled Aleph J
We agree 2SJ74 or LSJ74 is the right solution.
We also agree that LSJ689 is not the right solution solution.
We do not agree on J271 as an alternative to 2SJ74.
If I have to choose between J271 and say 2SJ313, I shall choose the latter, even for a power amp.
http://www.diyaudio.com/forums/pass-labs/267857-aleph-design-reloaded.html#post4184920
Cheers,
Patrick
We also agree that LSJ689 is not the right solution solution.
We do not agree on J271 as an alternative to 2SJ74.
If I have to choose between J271 and say 2SJ313, I shall choose the latter, even for a power amp.
http://www.diyaudio.com/forums/pass-labs/267857-aleph-design-reloaded.html#post4184920
Cheers,
Patrick
Which pmosfet do you recommend with comparable linearity or better than J271 at ~4-5ma bias Patrick?
Apparently Reichelt has 2SJ74 (Toshiba) in stock.
2SJ 74: Transistor 2SJ 74 chez reichelt elektronik
2SJ 74: Transistor 2SJ 74 chez reichelt elektronik
At only 3.23 euros, I am suspicious of their source.
Maybe worth asking for ONE sample and test it.
- Status
- Not open for further replies.